Unless sold and issued warrants are subject to the provisions of FASB ASC 815-10, the Company utilized a Black-Scholes options pricing model to value the warrants sold and issued. This model requires the input of highly subjective assumptions such as the expected stock price volatility and the expected period until the warrants are exercised. When calculating the value of warrants issued, the Company uses a volatility factor of 100%, a risk free interest rate and the life of the warrant for the exercise period.

The following table summarizes information about common stock warrants outstanding at September 30, 2019:

Note * 205,000 warrants exercisable at $0.35 contain dilution protections that increase the number of shares purchasable at exercise upon the issuance of securities at a price below the current exercise price.

On August 12, 2019, the Company issued 37,210 shares of common stock upon the cashless exercise of warrants to purchase 167,039 shares of common stock for $0.35 per share based on a market value of $0.45 per share as determined under the terms of the warrant.

From June through September 2019, the Company issued unsecured convertible notes and five-year warrants to unaffiliated accredited investors totaling $1,875,000. The notes are convertible into shares of common stock, with the initial conversion ratio equal to $0.50 per share. The investors received warrants to purchase a total of 1,875,000 shares of common stock with an exercise price of $0.70 per share. These securities were sold in reliance upon the exemption provided by Section 4(a)(2) of the Securities Act and the safe harbor of Rule 506 under Regulation D promulgated under the Securities Act. Using a Black-Scholes Valuation model these warrants had a value of $333,984 which was recorded as a discount on the notes payable and will be amortized over the life of the associated notes payable.